<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<header>网页头部</header>

<section>

    <h2>网页独立</h2>
</section>

<!--<footer>-->
    <!--<h2>网页底部</h2>-->
<!--</footer>-->

<!--<iframe src="//player.bilibili.com/player.html?aid=55631961&bvid=BV1x4411V75C&cid=97257967&page=11" scrolling="no" border="0" frameborder="no" framespacing="0" allowfullscreen="true"> </iframe>-->
<!--<iframe src="http://www.baidu.com" frameborder="0" width="1000px" height="800px"></iframe>-->

<input type="text" name="username" placeholder="请输入用户名"/>


</body>
</html>